💧 Diagnose

Which of the four flow faults do you have?

Weak everywhere, uneven at a few nozzles, leaking at the joint, or coming and going. Each has a different cause, and three of the four are a twenty-minute fix.

4 patternsDiagnose in 10 minNo special tools
Turn off water· Don't over-tighten· Rinse thoroughly

The one test that saves moneyRemove the head and run the open arm into a bucket. Strong flow there means the fault is in the head. Weak or surging flow means it is in the valve or supply — and no amount of descaling will fix it.

Four patterns at a glance. Click a name to jump to its detail.
PatternWhat you noticeMost common causeDifficultyTime
Weak Flow The whole head still sprays, but the water barely leaves the face. Inlet filter screen blocked with sediment or pipe debris EASY 20–40 min
Uneven Spray A few nozzles dribble or shoot sideways while the rest are fine. Calcium crust on individual nozzle orifices EASY 15 min + soak
Leak at Connection Water runs down the arm or drips from the collar, not the face. Rubber gasket deformed, hardened or missing EASY 10–20 min
Intermittent Flow Pressure surges and fades, or stops entirely for a few seconds. Cartridge worn or clogged, so the valve does not hold a steady opening CALL A PRO Diagnose 10 min

💧 Type 1 of 4

Weak Flow

EASY 20–40 min $0–12

Every nozzle is still working, there is just far less water than there used to be. This is the most common complaint and almost always a restriction upstream of the faceplate: the inlet filter screen, a clogged flow restrictor, or scale across the whole nozzle field.

What usually causes it

  • Inlet filter screen blocked with sediment or pipe debris
  • Flow restrictor clogged, or a low-flow disc fitted by the previous owner
  • Limescale film across the faceplate reducing every orifice at once
  • Supply valve partly closed, or a pressure drop elsewhere in the house

Checks, in order

  1. Run the shower with the head removed. Strong flow at the arm means the problem is in the head; weak flow there means it is in the valve or supply.
  2. Look into the threaded inlet. Most heads have a conical mesh screen sitting right at the opening.
  3. Check the rating stamped on the head or restrictor — 1.5 and 1.8 gpm heads feel weak next to an old 2.5 gpm unit.
  4. Open the shower valve fully and confirm no other fixture is running.

What fixes it

  • Rinse the inlet screen under a tap, then pick out embedded grit with a toothpick.
  • Soak the head face-down in white vinegar for 4–8 hours, then brush the nozzles.
  • If the restrictor is clogged, clean it before considering removal — and check local water-use rules first.
  • Replace a cracked or deformed screen; they cost a couple of dollars.

When to stopIf flow at the open arm is still weak with the head off, the cartridge or supply line is the problem. That is valve work, not shower-head work.

Repair guide 3DRehearse in 3D Read the article

💧 Type 2 of 4

Uneven Spray

EASY 15 min + soak $0–6

Localised blockage. Calcium and magnesium in hard water precipitate out on the nozzle orifices, and once one hole starts to crust over it collects more scale. Rubber nozzles can also be torn or pushed out of alignment, which throws the jet sideways.

What usually causes it

  • Calcium crust on individual nozzle orifices
  • Rubber nozzle tip split, hardened or missing
  • Grit lodged behind the faceplate after plumbing work
  • Faceplate slightly warped, so jets angle outward

Checks, in order

  1. Shine a light across the face at a low angle — scale shows as a white ring around the hole.
  2. Rub a finger across the nozzles. Rubber tips should flex; hardened tips are scaled through.
  3. Scrape a little of the white deposit into a cup and add vinegar. If it fizzes, it is calcium carbonate.

What fixes it

  • Soak the face in vinegar or a citric-acid solution, then scrub with a soft brush.
  • Clear stubborn holes with a toothpick — never a needle, which scratches the orifice.
  • Replace torn rubber nozzles if the head has a removable faceplate.
  • If scale returns within weeks, test your water hardness and consider a softener.

When to stopRecurring scale across a whole house points at water chemistry or the water heater, not the shower head. That is a job for a plumber or a water-treatment specialist.

Repair guide 3DRehearse in 3D Read the article

💧 Type 3 of 4

Leak at Connection

EASY 10–20 min $2–8

The joint between the shower arm and the head is sealed by a rubber gasket, not by thread tape. Over-tightening crushes and folds that gasket, which is why the leak often gets worse the harder you turn the head.

What usually causes it

  • Rubber gasket deformed, hardened or missing
  • Head over-tightened until the gasket folds out of its seat
  • Grit on the gasket face or on the arm threads
  • Cracked plastic collar, or crossed threads on the arm

Checks, in order

  1. Dry the joint, run the shower for 20 seconds, and watch where the first bead forms.
  2. Unscrew the head and inspect the gasket — a flat, hard or wavy ring needs replacing.
  3. Look at the arm threads for debris or a burr; both prevent the gasket seating.

What fixes it

  • Clean the gasket seat and the arm threads, then fit a new gasket.
  • Hand-tighten, then no more than a quarter to half turn with a wrench.
  • Only use thread tape on tapered metal-to-metal joints without a gasket — never as well as a gasket.
  • Replace a cracked collar rather than forcing it.

When to stopA leak that continues at the arm-to-wall joint, or water inside the wall, needs a plumber. Stop using the shower until it is fixed.

Repair guide 3DRehearse in 3D Read the article

💧 Type 4 of 4

Intermittent Flow

CALL A PRO Diagnose 10 min Varies

Flow that changes on its own is rarely the head. A sticking cartridge, debris moving inside the valve, or a partly frozen supply pipe all produce the same symptom. The diagnostic test is simple: take the head off and see whether the arm still behaves badly.

What usually causes it

  • Cartridge worn or clogged, so the valve does not hold a steady opening
  • Debris or scale moving inside the valve body
  • Exterior-wall pipe partly frozen in cold weather
  • Pressure fluctuation from another fixture, or a failing pressure-reducing valve

Checks, in order

  1. Remove the head and run the arm into a bucket. If the flow still surges, the head is innocent.
  2. Run a nearby tap at the same time — if both drop together, it is a supply issue.
  3. Note when it happens: first thing in the morning suggests pressure or freezing; random bursts suggest debris in the cartridge.
  4. Check whether the shower is on an exterior wall and whether the weather has been below freezing.

What fixes it

  • Clean or replace the cartridge if you are comfortable shutting off the water at the main.
  • Flush the valve body with the cartridge out to clear debris.
  • Insulate exposed pipe runs on exterior walls.
  • If a pressure-reducing valve is failing, have it replaced.

When to stopCartridge replacement means opening the wall plate and shutting off the supply. If you have never done it, or the valve is behind tile, call a plumber.

Repair guide 3DRehearse in 3D Read the article

Not sure which one it is?

The simulator walks the same decision tree, and shows you what each restriction looks like inside the head.

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